Evolutionary selection between alternative modes of gene regulation
Evolutionary selection between alternative modes of gene regulation
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DOI：
10.1073/pnas.0808500106
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发表时间：
2009-06-02
影响因子：
11.1
通讯作者：
Hwa, Terence
中科院分区：
文献类型：
--
作者：
Gerland, Ulrich;Hwa, Terence
微生物利用丰富的基因调控机制来调整其生长程序以适应环境的变化。很久以前就指出[Savageau M（1977）Proc Natl Acad Sci USA 74：5647-5651]，所采用的基因调控的特定模式可能与对受调控基因的“需求”相关，即，基因产物在其自然栖息地中需要的频率。一个进化的“使用它或失去它”的原则，提出了管理基因调控策略的选择。在这里，我们定量研究的力量选择和反对两种相反的基因调控模式，在进化模型的背景下，考虑到遗传漂变，突变和时间依赖性选择。我们考虑了时间依赖性选择的影响，强选择周期与中性进化周期交替。使用各种分析方法，我们发现有效的人口规模和典型的时间尺度的环境变化的关键参数确定的健身优势的不同模式的监管。我们的研究结果支持Savageau的使用它或失去它的原则，小人口与长时间尺度的环境变化，并支持一个互补的“磨损”的原则，相反的情况。
Microorganisms employ a wealth of gene regulatory mechanisms to adjust their growth programs to variations in the environment. It was pointed out long ago [Savageau M (1977) Proc Natl Acad Sci USA 74: 5647-5651] that the particular mode of gene regulation employed may be correlated with the "demand" on the regulated gene, i.e., how frequently the gene product is needed in its natural habitat. An evolutionary "use-it-or-lose-it" principle was proposed to govern the choice of gene regulatory strategies. Here, we examine quantitatively the forces selecting for and against two opposing modes of gene regulation, in the context of an evolutionary model that takes genetic drift, mutation, and time-dependent selection into account. We consider the effect of time-dependent selection, with periods of strong selection alternating with periods of neutral evolution. Using a variety of analytical methods, we find the effective population size and the typical time scale of environmental variations to be key parameters determining the fitness advantage of the different modes of regulation. Our results support Savageau's use-it-or-lose-it principle for small populations with long time scales of environmental variations and support a complementary "wear-and-tear" principle for the opposite situation.